The present invention relates to a shuttle device having a rotating hook for a sewing machine.
Shuttle devices having rotating hooks provided with an abutment mechanism utilizing an escapement oscillating under the action of a rotatable cam are well known. U.S. Pat. No. 3,217,678 discloses such a device which comprises a vertical shaft, a rotatable casing having a hook formed on the edge of the casing wall and rotatable on said shaft, a cam secured to the underside of said casing, a bobbin carrier rotatably supported in said casing, the carrier having on its upper surface a pair of spaced abutment faces, an escapement mounted for oscillation about an axis parallel to the shaft, the escapement having a pair of beaks cooperating with said abutment faces so that one beak is always in contact with a respective abutment face in order to prevent rotation of the bobbin carrier. In the course of operation alternate gaps are formed between cooperating beaks and abutments for the passage of the upper thread loop.
It has been found that such devices are prone to clogging or jamming when a part of a thread loop is caught between the engaging faces of the rotatable casing and the bobbin carrier. When such jamming occurs the bobbin carrier and outer casing are jammed together forcing the bobbin carrier to rotate with the outer casing which may result in deformation or injury to the beaks and other parts of the device.